الفهرس 
ContentsOnly 14 pages are availabe for public view
 |  | from | 254 |  |  |
| | | from | 254 | | |
Abstract
Three aquatic plants which were Azolla filiculoides Lam., Lemna minor L, and Pistia stratiotes L. were selected to study the biological efficiency of uptake of minerals (cadmium, chromium, lead and zinc). When Azolla filiculoides was exposed to different concentrations of chromium and lead, it showed a varying increase in absorption rate with concentrations during the experimental period compared to the control value. Also, the removal rate of heavy metals in the case of Lemna minor was high from 0 to day 3 and 6 of the experiment in the case of chromium and cadmium. Zinc results showed that after 12 days of exposure to different concentrations. The metal removal percentage from the solution by the plant increased compared to the control value. For lead, the lead content of the plant in the concentration was 10 and 20 mgL-1 higher than the tested lead concentrations in industrial wastewater. Pistia stratiotes exposed to different concentrations of cadmium, chromium, lead and zinc showed a differential increase in absorption rate during the experimental period compared to the control value. Also, some growth parameter such as fresh and dry weight and water content were calculated in the three studied plants during the experimental periods. Results showed that, the value of fresh and dry weight and water content increase in low concentrations in the first days of the experiment, while the opposite occurred in higher concentrations during the experiment period compared to the control value. The content of chlorophyll a, b and carotenoid were also determined in the tissues of the three studied plants and results showed that the value of the total pigment of the plants under study increases almost in the lower concentrations of the elements in the first days of the experiment and with increasing the concentrations of the elements and the days of the experiment the total pigment value decreases compared to control value. The enzymes responsible for the oxidation process were also calculated, which are catalase, peroxidase and polyphenol oxidase in the three plants under study during the experiment periods, as it was found that there were variation in the activity of the three enzymes during the experiment period compared to the control value. In this study results showed that the removal percentage, generally higher in case of three plant powder modified with silver nanoparticles.